1. Technical Field of the Invention
The present invention relates to cooling systems for cooling electronic equipment, and particularly to systems for cooling electronic equipment that are reconfigurable to allow customized air flow in proximity to the electronic equipment.
2. Background and Objects of the Invention
The growth of the computer industry and telephony over the past few decades has been phenomenal. The integration of these technologies, for example, in telecommunications switching systems, has lead to greater and greater efficiencies as larger numbers of communications are handled by fewer components, which are typically housed in a central control room. One problem inherent with many existing cooling systems for electronic equipment is inflexibility. Many existing cooling systems are built into and/or under the flooring of a temperature-controlled room having equipment needing to be cooled. Such cooling systems employ fixed conduits or other piping for directing cooled air along a subsurface of the flooring and upwardly through the floor and towards the equipment to be cooled. The upwardly directed cooled air is in proximity to the equipment. In the event the temperature characteristics within the temperature-cooled room changes, such as by the equipment being moved within the room or by additional equipment being added therein, it is very difficult to modify the cooling system accordingly. For instance, the conduits have to be detached from their fixed positions and repositioned or replaced in favor of differently sized conduits. Consequently, altering the cooling characteristics of existing cooling systems frequently proves a costly adventure. Floor-based cooling systems present additional difficulties other than inflexibility in cooling characteristics. For instance, floor-based cooling systems that do not utilize conduits for passing cooled air occupy more area so that equipment cabling and other obstructions do not cause uneven air distribution or a reduction in air pressure. Such systems require the equipment cabling to be plenum rated, thereby increasing system cost. Floor-based cooling systems also possess the tendency to distribute noise and vibrations, which may effect the operation of the equipment to be cooled.
In addition, floor-based and other existing cooling systems have a rather limited cooling capability. For instance, existing cooling systems have heat densities of approximately 80 watts per square foot (W/ft2) with planned cooling systems being claimed to possess heat densities of up to 150 W/ft2. Cooling systems having such heat densities, however, may not effectively cool today's equipment, such as state-of-the-art computational equipment.
Existing cooling systems typically sense the return temperature from, or the supply temperature to the whole room to control the capacity of the cooling system. Local adjustment of the cooling capacity is normally done by moving perforated tiles in the raised floor that are used for cold air distribution. This manual reconfiguration of a cooling system is inconvenient and time consuming.
As is readily apparent, if equipment is not effectively cooled, the internal temperature of the electronic components in the equipment substantially increases, thereby leading to significantly reduced system performance and, in some cases, total system failure. If a cooling system inefficiently cools the equipment, either the equipment may fail due to increased operating temperature or the costs for cooling the equipment may be unnecessarily high. What is needed, then, is a cooling system having its cooling characteristics closely tailored to the heating characteristics of the equipment to be cooled and that is adjustable in real time in response to changing local heat conditions.
One solution has been a ceiling-mounted cooling system comprising heat exchanger and a plurality of fans positioned below the heat exchanger as described in co-pending U.S. patent application Ser. Nos. 09/617,391; 09/635,374; and 09/617,213; each assigned in common herewith. When the fans are activated, heated air is drawn up through a first portion of the heat exchanger and then down through a second portion of the heat exchanger. This system is advantageous in that it is more easily configurable to the spatial heating requirements of the room, but it lacks the capability of automatic, real time adaptation to local heating requirements.